A Novel Method to Estimate the System Damping After Generator Tripping

Bin Zi-Jun,Liu Yun,Hao Si-Peng,Zhu Xin-Yao,Kong Xiang-Ping,Wang Ming-Shen 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.2

Generator tripping strategies are generally decided by offline transient stability analysis. However, traditional methods can hardly ensure dynamic stability after GT. Simulation tests show that GT strategies change the topology and the state variables of a power system, which may weaken the system damping after GT. In order to estimate the system damping, this paper proposes a time-varying linearized model under unsteady states based on the virtual equilibrium point (VEP) theory. Then, the changes in dynamic characteristics caused by GT can be represented by the eigenvalues at VEPs before and after GT. An inertia equivalence system is mathematically formulated to analyze the effects of generator inertia, damping ratio, and controllers. Two indices are designed to estimate the system damping changes. Based on the indices, a framework is proposed to improve the current GT strategy decision-making system. The sensitivity analysis and the fault scanning verify the effectiveness and robustness of the proposed method and indices.

Improved multi-carrier PAP reduction method based on PTS

Zi-bin Zhao,Young-Hwan Kim,Jae-Moung Kim 한국통신학회 2005 한국통신학회 학술대회논문집 Vol.2005 No.6

Construction and Characterization of Vitreoscilla Hemoglobin (VHb) with Enhanced Peroxidase Activity for Efficient Degradation of Textile Dye

( Zi Dong Zhang ),( Wei Li ),( Hai Chao Li ),( Jing Zhangi ),( Yue Bin Zhang ),( Yu Feng Cao ),( Jian Zhang Ma ),( Zheng Qiang Li ) 한국미생물 · 생명공학회 2015 Journal of microbiology and biotechnology Vol.25 No.9

Pollution resulting from the discharge of textile dyes into water systems has become a major global concern. Because peroxidases are known for their ability to decolorize and detoxify textile dyes, the peroxidase activity of Vitreoscilla hemoglobin (VHb) has recently been studied. It is found that VHb and variants of this enzyme show great promise for enzymatic decolorization of dyes and may play a role in achieving their successful removal from industrial wastewater. The level of VHb peroxidase activity correlates with two amino acid residues present within the conserved distal pocket, at positions 53 and 54. In this work, sitedirected mutagenesis of these residues was performed and resulted in improved VHb peroxidase activity. The double mutant, Q53H/P54C, shows the highest dye decolorization and removal efficiency, with 70% removal efficiency within 5 min. UV spectral studies of Q53H/P54C reveals a more compact structure and an altered porphyrin environment (λSoret = 413 nm) relative to that of wild-type VHb (λSoret = 406), and differential scanning calorimetry data indicate that the VHb variant protein structure is more stable. In addition, circular dichroism spectroscopic studies indicate that this variant’s increased protein structural stability is due to an increase in helical structure, as deduced from the melting temperature, which is higher than 90°C. Therefore, the VHb variant Q53H/P54C shows promise as an excellent peroxidase, with excellent dye decolorization activity and a more stable structure than wild-type VHb under high-temperature conditions.

지진 하중하에서 콘크리트 충전 강교각의 거동

정지만(Zung Zi Man),장승필(Chang Sung Pil),인성빈(In Sung Bin) 대한토목학회 2002 대한토목학회 학술대회 Vol.2002 No.11

Influence Factor on Magnetization Property of Carbonyl Iron-based Magnetorheological Fluids

Daoming Wang,Bin Zi,Sen Qian,Jun Qian,Yishan Zeng 한국자기학회 2016 Journal of Magnetics Vol.21 No.4

Magnetization property is a critical factor for magnetorheological fluids (MRFs) to achieve the liquid-solid transition. The main focus of this study is on exploring the influence factors on magnetization properties of MRFs. In this paper, a theoretical analysis is performed to discuss the magnetization characteristics of MRFs firstly. Then, a method for the preparation of carbonyl iron-based MRFs is illustrated and five MRFs samples with various material parameters are prepared. It is succeeded by a series of experiments on testing the hysteresis loop and the magnetization curve of each sample and the influence factors are compared and analyzed. Experimental results indicate that there is basically no hysteresis phenomenon on MRFs which exhibits superparamagnetic behavior at room temperature. A surfactant coating on magnetic particles can slightly improve the MRFs magnetization. Additionally, the magnetic susceptibility and the saturation magnetization both increase with the particle concentration, whereas the influence of particle diameter is relatively very small. Moreover, as the temperature increases, the magnetization decreases and the declining rate accelerates gradually.

P53 Arg72Pro Polymorphism and Bladder Cancer Risk - Meta-analysis Evidence for a Link in Asians but not Caucasians

Xu, Ting,Xu, Zi-Cheng,Zou, Qin,Yu, Bin,Huang, Xin-En Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.5

Objective: Individual studies of the associations between P53 codon 72 polymorphism (rs1042522) and bladder cancer susceptibility have shown inconclusive results. To derive a more precise estimation of the relationship, we performed this systemic review and meta-analysis based on 15 publications. Methods: We used odds ratios (ORs) with 95% confidence intervals (CIs) to assess the strength of the association. Results: We found that there was no association between P53 codon 72 polymorphism and bladder cancer risk in the comparisons of Pro/Pro vs Arg/Arg; Pro/Arg vs. Arg/Arg; Pro/Pro plus Pro/Arg vs. Arg/Arg; Arg/Arg vs. Pro/Arg plus Arg/Arg (OR=1.06 95%CI 0.81-1.39; OR=1.06 95%CI 0.83-1.36; OR=0.98 95%CI 0.78-1.23; OR=1.06 95%CI 0.84-1.32). However, a significantly increased risk of bladder cancer was found among Asians in the homozygote comparison (Pro/Pro vs. Arg/Arg, OR=1.36 95%CI 1.05-1.75, P=0.790 for heterogeneity) and the dominant model (Arg/Pro plus Pro/Pro vs. Arg/Arg, OR=1.26 95%CI 1.05-1.52, P=0.564 for heterogeneity). In contrast, no evidence of an association between bladder cancer risk and P53 genotype was observed among Caucasian population in any genetic model. When stratifying for the stage of bladder, no statistical association were found (Pro/Pro vs. Arg/Arg, OR=0.45 95%CI 0.17-1.21; Pro/Arg vs. Arg/Arg, OR=0.60 95%CI 0.28-1.27; Dominant model, OR=0.56 95%CI 0.26-1.20; Recessive model, OR=0.62 95%CI0.35-1.08) between P53 codon 72 polymorphism and bladder cancer in all comparisons. Conclusions: Despite the limitations, the results of the present meta-analysis suggest that, in the P53 codon 72, Pro/Pro type and dominant mode might increase the susceptibility to bladder cancer in Asians; and there are no association between genotype distribution and the stage of bladder cancer.

DFT and TD-DFT study on structure and properties of organic dye sensitizer TA-St-CA

Cai-Rong Zhang,Zi-Jiang Liu,Yu-Hong Chen,Hong-Shan Chen,You-Zhi Wu,WangJun Feng,Dao-Bin Wang 한국물리학회 2010 Current Applied Physics Vol.10 No.1

The geometry, electronic structure, polarizability and hyperpolarizability of organic dye sensitizer TA-St-CA, which contains a π-conjugated oligo-phenylenevinylene unit with an electron donor.acceptor moiety, was studied using density functional theory (DFT), and the electronic absorption spectrum was investigated via time-dependent DFT (TD-DFT) with several hybrid functionals. The calculated geometry indicates that the strong conjugated effects are formed in the dye. The TD-DFT results show that the hybrid functional PBE1PBE and MPW1PW91 are more suitable than B3LYP for calculating electronic absorption spectra. The features of electronic absorption spectra were assigned on account of the qualitative agreement between the experiment and the calculations. The absorption bands in visible and near-UV region are related to photoinduced electron transfer processes, and the diphenylaniline group is major chromophore that contributed to the sensitization, and the interfacial electron transfer are electron injection processes from the excited dyes to the semiconductor conduction band. Compared with the similar dye D5, the good performance of TA-St-CA in dye-sensitized solar cells may be resulted from the higher energy level of the lowest unoccupied molecular orbital and the larger oscillator strengths for the most excited states with intramolecular electron transfer character.

Power Distribution and Coordinated Control for a Power Split Hybrid Electric Bus

Feng Wang,Hu Zhong,Zi-Lin Ma,Xiao-Jian Mao,Bin Zhou 대한전기학회 2008 Journal of Electrical Engineering & Technology Vol.3 No.4

The power distribution is proposed to determine the target operating points of the system components as the basis for maximal the efficiency of the overall system for a power split dual electric machine hybrid electric bus. The coordinated control is constructed on the basis of the power distribution. The basic coordinated control is implemented to satisfy the driver's power demand, in which both the dynamic characteristics of the engine and the dual electric machine are explicitly taken into account. Moreover, the improved coordinated control is suggested to suppress engine dynamic operation and rich fuel injection.

Functional Roles of Long Non-coding RNA in Human Breast Cancer

Ye, Ni,Wang, Bin,Quan, Zi-Fang,Cao, San-Jie,Wen, Xin-Tian,Huang, Yong,Huang, Xiao-Bo,Wu, Rui,Ma, Xiao-Ping,Yan, Qi-Gui Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.15

The discovery of long noncoding RNA (LncRNA) changes our view of transcriptional and posttranscriptional regulation of gene expression. With application of new research techniques such as high-throughput sequencing, the biological functions of LncRNAs are gradually becoming to be understood. Multiple studies have shown that LncRNAs serve as carcinogenic factors or tumor suppressors in breast cancer with abnormal expression, prompts the question of whether they have potential value in predicting the stages and survival rate of breast cancer patients, and also as therapeutic targets. Focusing on the latest research data, this review mainly summarizes the tumorigenic mechanisms of certain LncRNAs in breast cancer, in order to provide a theoretical basis for finding safer, more effective treatment of breast cancer at the LncRNA molecular level.

Identification and expression profiling of six chemosensory protein genes in the beet armyworm, Spodoptera exigua

Jia-Ying Zhu,Sang-Zi Ze,Bin Yang 한국응용곤충학회 2015 Journal of Asia-Pacific Entomology Vol.18 No.1

Chemosensory proteins (CSPs) are believed to be important in the detection of semiochemicals, and have been reported to be involved in development, molting, leg regeneration and phase transition. In the current study, six CSP genes were identified in the beet armyworm Spodoptera exigua, namely SexiCSP1-6, from the full length cDNA library.Multiple alignment and phylogenetic analysis indicated that theywere very diverse as seen in CSPs of other insect species. Expression patterns determined by quantitative real-time PCR (qPCR) revealed that they were highly expressed in antenna. SexiCSP1-3, SexiCSP5 and SexiCSP6 were male antenna-biased, while SexiCSP4 was female-biased in the antenna. In addition to antenna, they were expressed at high levels in legs and wings, suggesting potential roles in contact chemoreception and non-olfactory roles. Compared with the expression in antenna, legs and wings, only SexiCSP1 showed relatively high expression in heads, thoraxes and abdomen. These results extended olfactory gene resource in the beet armyworm and provided basis for further gaining a better understanding of CSPs roles in this pest.